Generally, drinking water is produced by municipalities from a lake or ground water by treating the water with ozone or chlorine. Once the water is treated, it is transported to households by pipes. Over time, contaminants may infiltrate into the pipeline. Accordingly, even though the potable drinking water is fed into the pipeline from a water treatment facility, the water may be contaminated by the time it enters a residence. Further, if there is a breakdown in equipment at the water treatment facility or a flood, contaminated water may enter the pipeline.
A variety of domestic filtration systems have been developed for use by consumers to filter water that is delivered by a tap. Such systems may use a filter made from a combination of a porous media filter and activated carbon through which water is passed. This type of system will reduce the levels of chlorine, lead, and pesticides. However, there are several disadvantages associated with this device. In particular, a filtration system will not remove microbiological contaminants from water.
Another popular system in use for the purification of contaminated water is a system which employs ultraviolet light for disinfection in series with a porous media and carbon filter. This type of system will reduce the levels of chlorine, lead, and pesticides and has some disinfection capability. One disadvantage with this system is that the ultraviolet light's disinfection efficacy is greatly diminished by turbidity or colour in the water which can cause the filter to become contaminated by microorganisms which can readily live and breed therein thereby multiplying the danger from any microorganisms which may be present. Thus, the filter of this system also suffers from the disadvantages associated with filters of filtration based systems.
Water treatment apparatus using oxidizing gases have been developed. Some of these devices operate on a batch basis. According to this process, the water is placed in a treatment container and the treatment agent (e.g. a gas), is disbursed through the water, such as via a sparger. Following the completion of the cycle, the water may then be used. One disadvantage with small scale ozone treatment systems such as for domestic applications is to produce an effective amount of ozone to kill a variety of different microbiological agents that may be present in the water.